<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>gh-4988 (iframe part)</title>
</head>
<body>
    <button id="btn1">#btn1 no set</button>
    <button id="btn2" tabindex="2">#btn2 2</button>
    <iframe id="iframe1" src="./frame1.html"></iframe>
    <button id="btn6" tabindex="1">#btn6 1</button>
    <iframe tabindex="3" id="iframe2" src="./frame2.html"></iframe>
    <button id="btn10">#btn10 no set</button>
</body>
</html>
